Tribological performance of phosphonium based ionic liquids for an aluminum-on-steel system and opinions on lubrication mechanism

✍ Scribed by XuQing Liu; Feng Zhou; YongMin Liang; WeiMin Liu

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 924 KB
• Volume: 261
• Category: Article
• ISSN: 0043-1648
• DOI: 10.1016/j.wear.2006.03.018

✦ Synopsis

A series of asymmetrical tetraalkylphosphonium ionic liquids were synthesized and evaluated as a new kind of lubricant for the contacts of steel/Al using an Optimol SRV oscillating friction and wear tester in ambient condition. The phosphonium ionic liquid shows excellent tribological performance and is superior to the conventional ionic liquids 1-ethy-3-hexylimidazolium hexafluorophosphate (P206) in terms of anti-wear performance and load-carrying capacity. The chemical compositions of the boundary film generated on different contact surfaces were analyzed on a scanning electron microscope with a Kevex energy dispersive X-ray analyzer attachment (SEM/EDS) and X-ray photoelectron spectrometer (XPS). The friction-reduction and anti-wear mechanism were proposed to originate from the layered structure of ionic liquid under boundary lubrication and the tribochemical reaction of anions with the fresh surface, respectively.